Meiotic recombination is essential for the linkage of homologous chromosomes to prepare them for disjunction in meiosis I. This process is promoted by two recombinase enzymes, Rad51 and Dmc1 that have the ability to pair and exchange strands between homologous DNA molecules. While Rad51 has been characterized fairly well, little is known about the recombinase activity of Dmc1. This research project will employ a variety of biochemical methods and electron microscopy to (1) define the activities of a spliced form of hDmcl and examine whether this hDmcl variant physically and functionally interacts with the full length protein and (2) delineate the role that Rad54B plays in hDmcl-mediated recombination reactions. The proposed studies should shed some light on the action mechanism of hDmcl and make a significant contribution toward understanding meiotic recombination in humans. [unreadable] [unreadable]